摘要：Objective: The aim of the study was to propose a set of tests to clarify the diagn.sis of repeated implan.ation.failure in.patien.s un.ergoin. in.vitro fertilization.(IVF). Study design. Fifty-n.n. patien.s with at least two un.uccessful IVF attempts were in.luded in.the study. Blood samples were evaluated for the presen.e of un.erlyin. thyroid abn.rmalities, an.iphospholipid an.ibodies (aPL), in.reased levels of n.tural killer cells (n.), in.erited thrombophilia an. mouse embryo assay factor (MEAf). The same tests were performed on.20 n.rmal fertile con.rol patien.s. Results: Seven.y-six percen. of IVF patien.s showed at least on. abn.rmal result. This in.iden.e was higher with respect to that foun. amon. con.rol patien.s (45% ). The prevalen.e of thyroid abn.rmalities, aPL an. in.reased n. level was higher in.IVF patien.s whereas n. differen.es were observed in.terms of prevalen.e of in.erited thrombophilias an. MEAf. Con.lusion.: A better un.erstan.in. of reproductive failure mechan.sms should allow an.effective diagn.stic flow chart an. a focused therapeutic option.for patien.s experien.in. repeated IVF failure. With this objective in.min., our data provide two importan. results: thyroid abn.rmalities, aPL an. in.reased n. levels are more prevalen. in.women.experien.in. IVF failure. n. eviden.e was foun. for an.association.between.in.erited thrombophilia an. MEAf an. failure to achieve pregn.n.y after IVF.